1. Field of the Invention
The present invention relates to a transfer image forming method, a transfer image forming apparatus, and an intermediate transfer member to be used therein.
2. Description of the Related Art
Bleeding, which means such a phenomenon that inks applied adjacently to each other are mixed with each other, and beading, which means such a phenomenon that an ink that has impacted earlier is attracted by an ink that has impacted later, are known as problems at the time of the formation of an image by an ink jet system. In addition, there are problems such as curling and cockling due to excessive absorption of a liquid component in an ink by a recording medium.
A transfer ink jet printing method has been devised for solving the problems. The printing method includes the following steps:
(1) an intermediate image forming step of applying an ink containing a coloring material component onto an intermediate transfer member with an ink jet device to form an intermediate image; and
(2) a transferring step of pressing the intermediate transfer member having formed thereon the intermediate image against a recording medium to transfer the intermediate image onto the recording medium.
Here, in the transfer ink jet printing method, an improvement in transferability of the intermediate image onto the recording medium is an important objective.
Japanese Patent Application Laid-Open No. 2004-114675 exemplifies a transfer ink jet recording apparatus. In a printing method involving using the apparatus, after a wettability-improving component has been applied to an intermediate transfer member, an ink-flowability-reducing component is further applied onto the wettability-improving component and then an ink-jet-drawn image is transferred onto a recording medium with a pressure. Japanese Patent Application Laid-Open No. H06-122194 discloses that an intermediate transfer member is obtained by laminating an elastic layer on a metal element tube, and that an ink image formed on the elastic layer is heated by photoirradiation and then transferred.
The related art described in the foregoing involves such problems as described below. That is to say, in the transfer ink jet recording apparatus in Japanese Patent Application Laid-Open No. 2004-114675, the construction of a basic transfer recording apparatus is described. However, Japanese Patent Application Laid-Open No. 2004-114675 has no description concerning a technology for improving the transferability or detachability of an ink image from the intermediate transfer member. The transferability or the detachability is of concern particularly upon continuous printing at a high speed, and such problem has not been sufficiently investigated in the related art.
In the construction of the intermediate transfer member of Japanese Patent Application Laid-Open No. H06-122194, the thin elastic layer is laminated on the thick metal element tube. Accordingly, when an ink layer to be transferred is as thin as about 1 to 3 μm, the elastic layer cannot follow the irregularities of a paper surface at the time of the transfer and hence a transfer failure occurs.